n a late-night scrubbing spree, dozens of embarrassing and incriminating posts were deleted Tuesday evening from the Twitter account of a Florida woman who has been described as a star government witness in the George Zimmerman murder case, The Smoking Gun has learned.

The sanitizing of Rachel Jeantel’s Twitter account came as the 19-year-old Miami resident prepared to take the stand and testify about a phone call she had with Trayvon Martin immediately before the unarmed 17-year-old was shot to death by Zimmerman in February 2012.

In relating that conversation, Jeantel has told investigators that a “scared” Martin said he was being followed by an unknown white man who demanded to know what the teen was doing inside the Retreat at Twin Lakes, a gated community in Sanford, Florida. Jeantel contends that she heard Martin ask the man, “Why you following me for?” before she heard someone “bump” the teenager. “Next thing I hear…the phone is shut off,” Jeantel told investigators in an April 2012 interview.

Jeantel’s testimony may allow prosecutors to further portray Zimmerman, a 29-year-old neighborhood watch commander, as Martin’s pursuer, an armed aggressor who profiled the black teen before murdering him with a single gunshot to the chest.